Small lifestyle changes that increase moderate-intensity physical activity are as effective as a structured exercise program in improving long-term cardiorespiratory fitness and blood pressure, according to a study supported by the National Heart, Lung, and Blood Institute (NHLBI).

"This is great news for the millions of Americans who are not getting enough physical activity," said NHLBI Director Dr. Claude Lenfant. "The study shows how effective small changes in lifestyle can be, especially for those who have been sedentary."

The study was done by researchers at the Cooper Institute for Aerobics Research in Dallas, TX. The finding appears in the January 27, 1999, issue of the Journal of the American Medical Association. NHLBI is part of the National Institutes of Health.

Lack of physical activity is a major risk factor for heart disease and contributes to other illness. Heart disease is the leading cause of death for Americans. One of every two men and one of every three women aged 40 and under will develop coronary heart disease, the main form of heart disease.

Most Americans get too little physical activity. About one in four U.S. adults are sedentary and another third are not active enough to reach a healthy level of fitness.

The Federal Government recommends that adults try to get at least 30 minutes of moderate-intensity physical activity on most and preferably all days of the week.

But Americans often are stymied by such factors as lack of time, social support, and access to exercise facilities, along with bad weather, and a dislike of vigorous exercise.

To find an effective way around such barriers, the researchers enrolled 235 men and women, ages 35 to 60, in Project Active. At the outset, all of the participants were sedentary. None had cardiovascular disease but most were moderately overweight.

The participants were randomly assigned to one of two groups: a lifestyle group, in which 122 participants learned behavioral skills to help them gradually fit more physical activity into their daily routines; and a structured group, in which 115 participants used a fitness center for such traditional forms of vigorous exercise as aerobics, swimming, stair climbing, and walking.

Both groups learned behavioral skills to help them be physically active. However, participants in the lifestyle group received more individualized help to tailor their physical activity changes to their daily routines. For instance, they learned to keep track of their inactivity and activity, such as how much time they spent sitting, how many minutes of moderate-intensity physical activity they accumulated in a day, or, using a simple step counter, how many steps they took in a day. Examples of their lifestyle changes are: taking longer walks on the way to office meetings; walking around airports, instead of sitting while waiting for a plane; walking around a soccer field at children's games; and forming a walking club.

After 6 months, the structured exercise group had improved their cardiorespiratory fitness more than the lifestyle group. But the subsequent decline in cardiorespiratory fitness was greater in the structured exercise group.

After 2 years, both groups had significantly increased their physical activity and improved their cardiorespiratory fitness and blood pressure. Furthermore, most participants maintained their improvements.

"The results show that physical activity doesn't require a fitness center and high-intensity workouts," said Dr. Andrea Dunn, Associate Director, Division of Epidemiology and Clinical Applications, at the Cooper Institute, who was the Project Director and lead author of the study.

"People have more opportunities to add physical activity to their daily life than they might think," she continued. "Anyone can sit down and think about what he or she does in the course of a day and then see how to work in more activity through a simple change or two."

NHLBI's Lenfant noted that the recommended 30 minutes of moderate-intensity activity do not have to be done at once, but can be divided into periods of at least 10 minutes each.

"The beauty," added Dunn, "is that these changes are simple to do and they add up to an important health difference."